45 research outputs found

    Adsorption of Congo Red from Aqueous Solution using Doped Strontium Hexaferrite – Zero Valent Iron Nanocomposite: Kinetic, Isotherm, and Thermodynamic Studies

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    391-397This study has dealt with synthesis of doped strontium hexaferrite / zero-valent iron nanocomposite (SrFe12O19/nZVI) and adsorption of Congo Red (CR) dye by the nanocomposite from aqueous solution was evaluated. The adsorbent was characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) analysis and Scanning Electron Microscopy (SEM). Optimization of experimental conditions such as pH, initial concentration of pollutant, adsorbent weight, contact time, and temperature was done. Maximum removal efficiency was achieved at pH of 8.5, initial concentration of CR=20 μg mL-1, adsorbent weight of 0.12 g with 15 min contact time and 25ºC temperature. Langmuir isotherm with R2=0.9959 seems to have best fit to the CR adsorption results. Also, kinetic studies revealed that adsorption of CR was fitted to the pseudo-second-order model with R2=0.9969. In addition, thermodynamic parameters were evaluated

    Adsorption of Congo Red from aqueous solution using doped strontium hexaferrite – zero valent iron nanocomposite: Kinetic, isotherm, and thermodynamic studies

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    In this study, doped strontium hexaferrite / zero-valent iron nanocomposite (SrFe12O19/nZVI) was synthesized and its adsorption ability for removing Congo Red (CR) dye from aqueous solution was evaluated. Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and X-ray diffraction analysis (XRD) were used to characterize the adsorbent. Experimental conditions, including pH, initial concentration of pollutant, adsorbent weight, contact time, and temperature were optimized. Maximum removal efficiency was achieved at pH of 8.5, initial concentration of CR=20 μg mL-1, adsorbent weight of 0.12 g, contact time=15 min and temperature of 25ºC. The results of isotherms showed that Langmuir isotherm was suitable for describing CR adsorption with R2=0.9959. Also, kinetic models were investigated, and the data followed the pseudo-second order kinetic model with R2=0.9969. In addition, thermodynamic parameters were evaluated

    Effects of relative replacement of different levels of dehulled soybean meal (DHSM) with fish meal on growth performance of adult Persian sturgeon, Acipenser persicus

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    The present study was designed and implemented to evaluate the effects of relative replacement of different levels of dehulled soybean meal (DHSM) instead of fish meal on growth performance of adult Persian sturgeon (Acipenser persicus). In this study, a total of eighty 4-year-old Persian sturgeons (Acipenser persicus), with an average weight of 3850 g were fed with 8 isonitrogenetic and isolipidic diets for 52 weeks. Experimental diets include different percentages of dehulled soybean meal include 0, 10, 15, 20% without amino acid, 15 and 20% replacement with lysine and methionine, and 15 and 20% replacement with lysine and methionine and L-carnitine supplement (DHSM0, DHSM10, DHSM15, DHSM20, DHSM20+AA, DHSM15+AA, DHSM20+AA+L.car. DHSM15+ AA+L.car.). After 52 weeks, no significant difference was observed between weight gain (WG), specific growth rate (SGR), LX and PV in different treatments. The protein efficiency ratio and feed efficiency (FE) in DHSM0 was significantly higher than that of DHSM20+AA and DHSM15+AA. Hepatosotic index of fish in DHSM0, DHSM10, DHSM15, DHSM20 + AA+L.car. DHSM30 + AA+L.car. was significantly higher than that in DHSM30 + AA. Gonadosomatic index exhibited alterations under the influence of the diet.  Effect of diets containing dehulled soybean meal with L-carnitine supplement on the reproductive system of female fish was significant and positive. The somatic growth in female Persian sturgeon was higher than that of males. However, their gonadic growth and stages of sexual maturity were significantly lower than that in males. The highest sexual maturity index of male fish was observed in DHSM15 + AA+L.car diet, so that at the end of the rearing period, 75% of fish were in stage IV of sexual maturity and 25% in stage III-IV. Addition of L-carnitine and essential amino acid supplement such as lysine and methionine to the diet containing soybean meal displayed a positive effect on the growth and reproductive indicators in the functional diet of Persian sturgeon and probably can improve significantly the production of Persian sturgeon fry

    Use of nanomaterials in the pretreatment of water samples for environmental analysis

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    The challenge of providing clean drinking water is of enormous relevance in today’s human civilization, being essential for human consumption, but also for agriculture, livestock and several industrial applications. In addition to remediation strategies, the accurate monitoring of pollutants in water sup-plies, which most of the times are present at low concentrations, is a critical challenge. The usual low concentration of target analytes, the presence of in-terferents and the incompatibility of the sample matrix with instrumental techniques and detectors are the main reasons that renders sample preparation a relevant part of environmental monitoring strategies. The discovery and ap-plication of new nanomaterials allowed improvements on the pretreatment of water samples, with benefits in terms of speed, reliability and sensitivity in analysis. In this chapter, the use of nanomaterials in solid-phase extraction (SPE) protocols for water samples pretreatment for environmental monitoring is addressed. The most used nanomaterials, including metallic nanoparticles, metal organic frameworks, molecularly imprinted polymers, carbon-based nanomaterials, silica-based nanoparticles and nanocomposites are described, and their applications and advantages overviewed. Main gaps are identified and new directions on the field are suggested.publishe

    Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

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    Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries
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